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Environmental Effects of Tidal EnergyOutcomes of a Scientific Workshop
Brian PolagyeUniversity of Washington
Northwest National Marine Renewable Energy Center
PICES 2010October 27, 2010
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Environmental Effects
Workshop Overview
Challenges
Recommendations
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Tidal Energy Devices
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“Typical”
Sites and Devices
2‐4 m/s
20‐60 m
Foundation
Drive
TrainRotor5‐20 m10‐30 rpm
Gearbox‐Generator
Direct Drive Generator
Pile Gravity Base
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Environmental Stressors
Device presence:Dynamic effects
Device presence:Static effects
Electromagnetic
effects
Acoustic effects
Chemical effects
Energy
removal
Cumulative Effects
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Environmental Receptors
Near‐field
environment
Far‐field
environment
Ecosystem Interactions
Benthic habitat
Pelagic habitat
Marine
mammals
Fish (migratory and resident)
Seabirds
Invertebrates
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Environmental Assessment Framework
Boehlert, G. and Gill, A. Environmental and Ecological Effects of Ocean Renewable Energy Development, Oceanography,
2010
Level 1Level 1
Level 2Level 2
Level 3Level 3
Level 4Level 4
Level 5Level 5
Type of Marine Renewable Energy
Stressors
Receptors
Level 6Level 6
Environmental Effect (frequency and duration)
Environmental Impact (type and severity)
Cumulative Effects (scales and context)
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Environmental Effects
Workshop Overview
Challenges
Recommendations
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Need for Workshop
Major interest in developing hydrokinetic energy in the U.S.
Environmental compatibility of technology stated without proof.
Environmental uncertainties present a major barrier to projects getting in the water at any scale.
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Technology Scope
Tidal HydrokineticsTidal Hydrokinetics Tidal BarrageTidal Barrage River Hydrokinetics
River Hydrokinetics
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Geographic Scope
Coastal Maine
Puget Sound
Southeast Alaska
Cook InletAleutian Islands
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Session Chairs Discussion4 hours
Receptors2.5 hours
Stressors1.5 hours
Wrap Up1.5 hours
Plenary Sessions4 hours
Stressors2.5 hours
Workshop Structure
Day 1
Day 2
Day 3
Participant Feedback: Another day would have been useful
Participant Feedback: Another day would have been useful
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Workshop Participants
US West Coast (CA, OR, WA, AK)
US East Coast
Europe
Canada
Universities
Agencies/NGOs
Research Labs
Industry
Specific technical or scientific expertise
Representative distribution of affiliation
Interest greatly exceeded capacity
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Relative Significance and Uncertainty
Color denotes
significance
Environmental receptor
Stressor
element
LowMediumHigh
Unknown
Not Applicable
Symbol denotes
uncertainty
?
LowMediumHighUnknown
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Presence of Devices –
Static EffectsPilot Scale
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Presence of Devices –
Static EffectsCommercial Scale
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Identification of Priority InteractionsSelection Criteria
—High potential significance
—High uncertainty
Summarize Key Information
—Description
—Gaps in Understanding
—Monitoring Approaches
—Mitigation Measures (stressor only)
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Workshop Report
Will be published as NOAA Tech Memo
Draft out for review to participants by end of week
Details of breakout sections
Challenges indentified
Recommendationshttp://depts.washington.edu/nnmrec/workshop
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Environmental Effects
Workshop Overview
Challenges
Recommendations
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Project Environmental Data are Scarce
Single device5 m diameterInstallation
effects only
CleanCurrent
Single device2 x 16 m diameterAcoustic effectsMarine mammal
behaviorSeabird behaviorBenthic habitat
MCT
Single device6 m diameterAcoustic effectsFish behaviorBenthic habitat
Open Hydro
Array5 m diameterFish behaviorSeabird behaviorBenthic habitat
Verdant Power
Single device3m diameter*Acoustic effectsMarine mammal
behaviorFish behavior
ORPC
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Information Needs at Pilot ScaleStressor Priority Area Before Pilot During Pilot
Presence of
devices: static
effects
Effects of
static
structures on
benthic
ecosystems
Characterize benthic
habitat.
Characterize species
presence/absence and
behavior.
Disruptions to benthic
habitat
installation/recovery.
Rate at which structures
are colonized.
Fish and marine mammal
interactions with modified
benthic ecosystems.
Presence of
devices:
dynamic
effects
Potential for
direct
interactions of
marine species
with turbine
rotor
Characterize movements
of marine mammals, fish,
and seabirds at temporal
and spatial scales required
to assess potential for
direct interactions.
Types of interactions and
at what frequency they
occur.
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Information Needs at Pilot ScaleStressor Priority Area Before Pilot During Pilot
Chemical effects Approaches to
preventing
biofouling are
poorly defined
Assess potential impacts
of anti‐fouling biocides.Fate of chronically
released biocides.
Acoustic effects Behavioral
responses to
increases in
broad band
noise
Behavioral response of
species to acoustic
signals.
Measurements of sound
pressure levels from
device operation.
Electromagnetic
effects
Electromagnetic
fields from
operating and
idle devices
Laboratory studies of
electric and magnetic
fields.
Models of electric and
magnetic fields from
proposed devices.
Measurements of
magnetic fields from
energized cables and
operating devices.
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Challenges to “Deploy and Monitor”Monitoring technologies are underdeveloped
—Existing methods focused on population effects
—Existing methods may not function in tidal energy environments
Difficulty of predicting, detecting, and attributing changes to tidal energy devices
Legal protections or ethical considerations prohibit studies of some interactions
Some important effects can only be measured at commercial scale
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Environmental Effects
Workshop Overview
Challenges
Recommendations
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Preliminary Research Prioritization
Marine mammal‐device interactions—Blade strike—Acoustic effects
Fish‐device interactions
Environmental tipping points for energy removal
7 receptors
x
≈6 elements
x
7 stressors
x
≈
6
elements
≈
1700 potential
interactions
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Pilot Projects are Required
Recognized need by participants of all affiliation
Must be well‐monitored
Prioritize objectives
Use common protocols
Courtesy of Marine Current Turbines
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Develop Assessment CapabilitiesClose monitoring instrumentation gaps—Detect, classify, and identify marine organisms at a
variety of scales—Real‐time monitoring for decision making
General monitoring protocols—Objective of data collection—Type of data to be collected—Mechanisms for data collection
Numerical models—Turbine scale: hydrodynamics, fish interactions—Regional scale: tipping points
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Mitigate Impacts when PossibleStressor Priority Area Recommended MitigationPresence of
devices: static
effects
Effects of static
structure on
benthic ecosystems
Minimize anchor sizes.
Minimize number of moorings and slack lines.
Streamline support structures.
Presence of
devices:
dynamic effects
Potential for direct
interactions of
marine species with
turbine rotor
Increase visibility of rotors to fish.
Acoustic avoidance measures.
Shock absorbers on leading edges of blades.
Temporary device shutdown.
Electromagnetic
effects
Behavioral
disruption from
electric and
magnetic fields
Bury power cables.
Twist cores for AC cables.
Run DC cables of opposing polarity in close
proximity.
Cumulative
effects
Effects on large,
mobile species
Limit number of devices at a given location
until effects of operation are sufficiently
understood.
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Collaboration is EssentialInformation needs to be shared between projects—IEA‐OES Annex IV—Significant intellectual property concerns
Hydrokinetic industry needs to engage with the oceanographic community—Leverage active areas of research
Expand opportunities for interdisciplinary collaboration
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AcknowledgementsWorkshop organizing committee—Andrea Copping, Pacific Northwest National Laboratory—Keith Kirkendall, NOAA Fisheries—George Boehlert, Oregon State University—Michelle Wainstein, University of Washington—Sue Walker, NOAA Fisheries—Brie Van Cleve, Pacific Northwest National Laboratory
Workshop sponsors—NOAA Fisheries—US Department of Energy
Workshop participants, particularly session chairs and note takers